Mystery 'Goo' Kills 200 Birds In San Francisco Bay Area

Tests are being carried out on dead seabirds found coated with a mysterious substance that looks and feels like dirty rubber cement.

About 200 dead birds have been found along the San Francisco Bay Area’s shorelines, said Andrew Hughan, spokesman for the California Department of Fish and Wildlife.

The goo covers their feathers, and the birds lose their ability to insulate themselves. They eventually freeze to death.

Tests are being carried out on the unidentified substance which has so far claimed the lives of 200 seabirds

Hughan said the wildlife agency's preliminary tests show the gray gunk is not a petroleum-based substance or an organic product like vegetable or fish oil. Final results might not come until later this week.

"You can't rush science," Hughan said. "It will be what it is, when it is."

Officials say the substance is not a public health or safety risk to humans.

They are investigating whether it could be polyisobutylene, a sticky, odorless and largely colorless material that killed thousands of seabirds in the United Kingdom in 2013.